Apparatus for producing theatrical effects



Jan. 2, 1934. s EDWARDS r AL 1,941,740

APPARATUS FOR PRODUCING THEATRICAL EFFECTS Filed Oct. 8, 1929 I l l l lll Patented Jan. 2, 1934 PATENT OFFiiIE APPARATUS FOR PRODUCING THEATRICAL EFFECTS Paul S. Edwards, Fort Meade, Md., and Constantin D. Barbulesco, Dayton, Ohio Application October 8, 1929. Serial No. 398,255

2 Claims.

This invention relates to means for producing theatrical effects.

Broadly, the invention comprehends a three element vacuum tube connected in a special circuit, inductively or directly connected to an antenna, and having in the plate circuit thereof means for controlling certain instrumentalities.

It is well established that theatrical and cinematographic arts rely upon the production of terest, possessing novelty and of great appeal to the public.

An object of the invention is to provide means for producing theatrical effects concomitantly with the movement of an artist on the stage.

Another object of the invention is to provide means for producing theatrical efifects simultaneously with the movement of an artist on the stage without efiort or the manual movement of mechanical devices. A further object of the invention is to provide means for producing theatrical effects so arranged that different effects may be produced concomitantly with the movement of the artists on the stage through different zone or area.

Other objects of the invention will appear from the following description taken in connection with the drawing, which forms part of the specification and in which:

Figure 1 is a schematic view of a circuit em ployed in connection with the invention, and

Figure 2 is a plan view of a theater illustrating the invention as applied.

Referring to the drawing for more specific details of the invention, 10 represents generally a vacuum tube having a filament 11, a grid 12 and a plate 13 enclosed within an evacuated envelope or container 14.

Connected to the input and output circuits of the tube is a loW loss tank circuit comprising a large variable capacitance 15 and a small inductance 16. The value of this capacity and inductance determine and control the frequency at which the tube oscillates.

Connected to the filament 10 are high frequency choke coils 1'7 and 18. These are composed of a relatively large number of turns of wire and are connected respectively in the grid and plate circuit of the tube.

When in operation, these choke coils introduce or generate two driving electromotive forces which maybe considered substantially 180 out of 60 phase. The geometric sum of these separate electromotive forces introduce and maintain a heavy oscillating current in the circuit. A third choke coil 19 is connected to the filament and serves to maintain it at high potential with re- 5 spect to the ground.

The electrical supply for the tube comprises a filament battery 20 and a plate battery 21 both of which are maintained at ground potential, and bypass condensers 22 and 23 of large value permitting circulation of high frequency currents are connected in the plate circuit.

The frequency at which the tube operates is controlled mainly by the value of the condenser 15 and the inductance 16. The condenser 15 is of large value and hence the interelectrode capacity of the tube becomes substantially negligible in effect.

Connected in the grid circuit is a grid condenser 24 and a leak resistance 25. The value of the condenser and resistance is so chosen that the high frequency oscillations generated in the tank circuit will periodically charge the condenser up to a certain value and then discharge through the leak resistance to the ground. Therefore, the condenser 24 and the resistance 25 produce a periodic interruption or chopping of the high frequency oscillations.

Connected in the output circuit of the tank is a sensitive relay 26 and a meter 27. The relay 26 is connected with a potentiometric arrangement 28 and 29 which opposes the current flowing from the filament to the plate battery, and the meter 27 is adapted to indicate the total value of the plate current.

The sensitive relay 26 comprises a movable coil 30 positioned in the magnetic field of a magnet 31. A pointer 32 is carried by the coil 30 and is suitably connected through a battery 33 to a circuit having connected therein relays 34 and 35 and suitable contacts 36 and 37 adapted to be engaged by the pointer 32 to close the circuit.

When the pointer 32 engages the contact 36, the relay 34 is actuated to close a circuit, not shown, to indicate that the oscillator is out of order, and when the pointer engages the contact 37, the relay 35 is actuated to close a circuit having arranged therein a lamp 38.

An exterior circuit comprising a loading coil 39 and conductors 40 and 41 is inductively cou- 2 h 1,94i,740 g pled to the tank circuit. This coupling may be utilized for inducing losses in the :tank circuit to increase the frequency of the periodic oscillations and eiTect a corresponding increase in the value of the plate circuit..

Figure 2 illustrates a floor plan of a theater comprising the conventional stage 42, orchestral 43, orchestra pit 44 and a balcony 45 having a rail 46. Arranged upon the stage is the conventional back drop 47 and wings 48. It is, of course, to be understood that the drop andwings and such other properties as may be necessary to play" may be varied in accordance with the character of the play being produced. a

Suitably located at the back of the stage is a plurality of oscillators 49, arranged in spaced relation, with respect to each other, and induce ,tively connected to the oscillators are antennas 50 preferably arranged in parallel relation with respect to each other and at equal distance apart. The antennas are suitably supported and insulated as indicated at '51.

It is, of course, to be understood that the antennas are theequivalent of the exterior circuit including the loading coil 39 and conductors 40 and 41, and that the oscillators 49 include a circuit corresponding to the circuit disclosed in Figure 1.

Connected in:the output circuits of the oscillators are suitable relays 52 connected as by conductors 53 and 54 to spot lights 55 arranged in spaced relation on the rail 46 of the balcony or otherwise suitably supported.

It will be observed that the antennas 50 are arranged in electrostatic relation to the stage so that any movement of the artists thereon and in relation to the field of one or more of the antennas will cause a reactance change in the oscillator which will close the associated relay and flight the lamp connected in the circuit controlled by the relay, it of course is understood that the lamps are so positioned and arranged that light will be thrown or projected on the stage.

It is evident that many combinations and effects may be produced as a result of the association of the various impelling or acting changes upon the oscillator. These changes may be in the form of light, heat, sound, movement or other physical changes acting upon the antenna or input circuit which may actuate other means connected in' the output circuit of the oscillator to produce the desired effect.

As an example, the action of a play can be arranged so that characters therein, when dressed in chemically treated make-up or cosup of the character. It is, of course, understood, that such combinations with the exception of the use of the sensitive oscillator which is the basis of this invention are more or less old in the arti While preferred embodiments of the invention have been described, it is to be understood that these are given merely as examples of the underlying principles of the invention, and since these may be incorporated in other specific mechanical structures, we do not intend to be limited to those shown except as such limitations are clearly imposed by the appended claims.

Having thus described the various features of the inventiomwhat we claim as new and desire to secure by Letters Patent, is:- i

1. An apparatus for producing theatrical effects comprising a self modulated high frequency oscillator embodying a tank circuit having low inductance, larger capacitance and low losses, connected across the grid and plate of the oscillator, a coil between the filament and grid and a second coil between the filament and plate of the oscillator, the oscillator being adapted to be concealed in proximity to a theater stage, an external circuit including an antennainductively coupled to the tank circuit, the antenna terminating adjacent a point on a stage where light is selectively desired, said antenna including" within its zone of action the area traversed by an actor and being adapted to change in capacity upon'the approach or recession of the actor with respect to the zone and a relay connected in the plate circuit of the oscillator for controlling a circuit including a lamp located oil the stage, adapted to project light on the actor entering the zone of action of the antenna.

2. An apparatus for producing theatrical effects comprising a plurality of oscillators, each having an electronic tube oscillator producing frequency oscillations modulated at audio frequency, a tank circuit having alow loss: coil and a condenser connected between the plate and grid of each oscillator, the oscillator being adapted to be concealed in proximity toa theater stage, open oscillating circuits inductively coupled to the respective tank circuit, including antennas terminating at selected pointsadjacent the stage, said antennas including within their zones of action the area traversed by an actor and being adapted to change in capacity upon.

the approach or recession of the actor with respect to the zones and lamps controlled by relays connected in the plate circuits of the differ ent oscillators for'projecting light rays on the actor entering the zones of the antennae and successively upon entering the field surrounding another of the antennas.

' PAUL S. EDWARDS.

CONSTANTIN D. BABBULESCO. 

